Bookmark

Quantum Physics

Title:Security Proof of a Semi-Quantum Key Distribution Protocol: Extended Version

Abstract: Semi-quantum key distribution protocols are designed to allow two users to
establish a secure secret key when one of the two users is limited to
performing certain "classical" operations. There have been several such
protocols developed recently, however, due to their reliance on a two-way
quantum communication channel (and thus, the attacker's opportunity to interact
with the qubit twice), their security analysis is difficult and little is known
concerning how secure they are compared to their fully quantum counterparts. In
this paper we prove the unconditional security of a particular semi-quantum
protocol. We derive an expression for the key rate of this protocol, in the
asymptotic scenario, as a function of the quantum channel's noise. Finally, we
will show that this semi-quantum protocol can tolerate a maximal noise level
comparable to certain fully quantum protocols.